Pregnancy diagnosis is widely practiced in cattle production systems. Ultrasonography is an alternative technique to rectal palpation for pregnancy diagnosis. Fetal losses caused by rectal palpation are well documented; however, reported losses from ultrasonography for pregnancy diagnosis are often confounded by normal embryonic losses during early gestation. Losses caused by inexperienced technicians have been reported previously, but limited information is available on technicians that are in the learning process. Our objectives were to compare fetal losses from pregnancy diagnosis during early gestation for 1) stage of gestation at the time of diagnosis (<53 or ≥53 d), 2) method of diagnosis (ultrasonography or rectal palpation), and 3) different skill levels of the technicians (novice or experienced). Beef heifers (n=2,190) exposed to natural service for 27 d, followed by diagnosis of pregnancy between 42 and 74 d of gestation were used to evaluate these objectives. Overall loss was 1.55%. Risk of loss was greater (P<0.01) in heifers <53 d pregnant compared with heifers ≥53 d (3.46 vs. 1.26%; a 2.74-fold increase) at the time of evaluation. Greater fetal loss (P=0.051) occurred with rectal palpation than with ultrasonography (2.68 vs. 1.29%; a 2.08-fold increase). Heifers evaluated by inexperienced technicians had a 2.07% fetal loss, whereas heifers evaluated by experienced technicians had only a 1.06% loss (P<0.01; a 1.95-fold difference). Cattle producers and veterinarians should recognize the importance of stage of pregnancy, level of technician experience, and method of diagnosis used to reduce losses attributable to pregnancy diagnosis.

The objective of this study was to determine whether a second injection of gonadotropin-releasing hormone (GnRH) at 54-h timed AI (TAI) of a CO-Synch/ CIDR (controlled internal device release) protocol improves fertility in replacement beef heifers. Heifers (n = 375) at three locations (Colorado, Wyoming, and South Dakota) were stratified by BW within body condition score (BCS) and randomly allotted to one of two treatments. All heifers received 100 µg of GnRH and a CIDR insert (d–7), followed by CIDR removal and 25 mg of prostaglandin F2α (PG; d 0). On d 2, control and treatment heifers underwent TAI at 54 h post-PG, and treatment heifers received a second 100-µg injection of GnRH. Blood samples were collected from all heifers at Colorado and Wyoming (d–17 and –7) to determine pubertal status. Ultrasonography was used to determine ovulation rate after TAI from a subsample of heifers (Colorado, n = 19; Wyoming, n = 49). No treatment x location interaction (P>0.10) occurred and pooled TAI pregnancy rates were similar (P>0.01) for control (46%) vs treatment (55%) heifers. Pubertal rates were greater (P<0.01) for heifers at Colorado (97.4%) than for heifers at Wyoming (46.4%); however, TAI pregnancy rates were similar (P> 0.10) for pubertal and prepubertal heifers. Ovulation rates tended to be different (P=0.10) for treatment (81.3%) than for control (62.5%) heifers. We conclude that the second injection of GnRH at TAI in the CO-Synch/CIDR protocol does not increase pregnancy rates to TAI in beef heifers, but that it may be economically viable and may guard against reduced fertility.

Crossbred, multiparous beef cows (n = 178 in Year 1; n = 148 in Year 2) were used to evaluate the effects of Cu, Zn, and Mn supplementation and source on reproduction, mineral status, and performance in grazing cattle in eastern Colorado over a 2-yr period. Cows were stratified by expected calving date, age, BW, BCS, and liver mineral status and assigned to the following treatments: 1) control (no supplemental Cu, Zn, or Mn); 2) organic (ORG; 50% organic and 50% inorganic Cu, Zn, and Mn); and 3) inorganic (ING; 100% inorganic CuSO4, ZnSO4, and MnSO4). Free-choice mineral feeders were used to provide current NRC-recommended concentrations of Cu, Zn, and Mn from 82 d (Year 1) and 81 d (Year 2) before the average calving date of the herd through 110 d (Year 1) and 135 d (Year 2) after calving. At the end of Year 1, supplemented cows had greater liver Cu (P < 0.01), Zn (P < 0.05), and Mn (P < 0.01) concentrations compared with controls, whereas liver Cu concentration was greater (P < 0.01) in ORG vs. ING cows. At the end of Year 2, supplemented cows had greater (P < 0.01) liver Cu concentrations relative to controls, whereas control cows had greater (P < 0.02) liver Mn concentration than did supplemented cows. In Year 1, pregnancy rate to AI in control cows did not differ (P = 0.47) from supplemented cows, but there was a trend (P < 0.08) for pregnancy rate to be higher for ORG than ING cows. In Year 2, supplemented cows had a higher (P < 0.02) pregnancy rate to AI than controls. In both years, when cows were inseminated after an observed estrus, supplemented cows had a higher (P < 0.04) pregnancy rate than did controls. Also, for both years, overall 60-d pregnancy rate tended (P = 0.10) to be higher for supplemented cows than for controls. In Year 1, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and kilograms of calf weaned per cow exposed was greater (P < 0.01) in ING than ORG treatments. However, in Year 2, kilograms of calf weaned per cow exposed was greater (P < 0.02) in controls than in supplemented cows, and tended (P = 0.09) to be greater in ORG than ING treatments. Results indicate that supplementation and source of trace minerals affected mineral status and kilograms of calf weaned per cow exposed in grazing beef cows. Supplementation also improved pregnancy rate to AI compared with cows not supplemented with Cu, Zn, or Mn for more than 1 yr. Furthermore, mineral source may influence pregnancy rate to AI.

A self-determining control circuit is configured to assume one of several states depending upon the interconnections of its input and output terminals. The self-determining circuit is enabled to sense which, if any, of its input and output have been interconnected and assume its proper state of operation. For example, a self-determining integrated circuit may have four input terminals (e.g., terminals 1, 2, 3, 4 ) and four output terminals (e.g., terminals A, B, C, D). The circuit may sense that a particular input terminal is directly connected with a particular output terminal (e.g., input terminal 2 is shorted to output terminal D) and operate under one set of parameters. If, however, the control circuit senses that a different set of terminals are interconnected (e.g., input terminal 4 with output terminal B), then the control circuit may operation under a different set of parameters. Similarly, if the control circuit senses that none of the terminals are interconnected (or connected to a supply potential), then it may operate under yet a different set of parameters.

A national sample of cow–calf producers was contacted to participate in a study to describe selected calving management practices on operations throughout the United States. Information was gathered on calving season, frequency of dystocia, frequency of observation, timing of assistance, and calving facilities. Regional and herd size differences existed in all parameters evaluated. Most calves (63.9%) were born in the months of February, March, and April. Overall, 16.7% of heifers and 2.7% of cows required some level of assistance in calving. Heifers and cows were checked an average of only 3.6 and 2.5 times per 24h period during the calving season. Producers allowed heifers to labor for an average of 2.8h prior to lending assistance in calving while cows were allowed an average of 3.5h before providing assistance. In addition, only 39.6% of calvings took place in specialized calving areas presumably to allow increased observation frequency, timely intervention and protection from the elements. Collectively, these management practices illustrate that opportunities exist to improve calf survivability and increase reproductive efficiency in many cow herds.

Breeding soundness examinations (BSE) were performed on 327 bulls at three locations in Wyoming and Montana. Scrotal circumference (SC), scrotal volume (SV), and body condition score (BCS) data were also collected. The animals were classified as yearlings, 2-yr-olds, or mature bulls. Age class and BCS had significant (P<0.01) effects on SC. Age class also accounted for significant (P<0.01) variation in SV. The correlation between SC and SV was 0.88. Scrotal circumference, SV, and pelvic area (PA) were measured and adjusted for age on the 139 yearling bulls at Location 1 (MT) to allow comparison with other age-adjusted traits. The linear regression of SC on age was 0.023 cm/d (P<0.05). Scrotal circumference and age were significant (P<0.01) sources of variation for the percentage of motile sperm (MOT). Composite yearling bulls had larger (P<0.05) adjusted SV, adjusted SC, pelvic height (PH), and percentage of MOT than Red Angus yearling bulls. The simple correlation between adjusted SC and adjusted yearling BW was 0.33 (P<0.05). Actual SC and SV were positively correlated with actual BW, actual hip height (HH), and percentage of MOT. Scrotal volume and percentage of MOT were positively correlated (0.22) (P<0.05). Our results indicate that SV could be used interchangeably with SC as a measure of sperm- producing capacity in beef bulls. Results of this study indicate that selecting bulls with larger SC or SV should result in increased yearling BW, greater PA, and bulls with improved fertility.

In humans, abnormal hair whorl patterns on the scalp are found in children with developmental disorders such as Down's syndrome and Prader-Willi syndrome. Previous research has shown that hair whorl position on a bovine's forehead may be related to temperament. The objective of this study was to determine the relationship between spermatozoal morphology and facial hair whorl epicenter. Breeding Soundness Evaluations (BSE) were given to 150 Angus yearling bulls (avg. age = 364 ± 1.4 days of age) from 3 different locations. Animals had 1 (n = 120), 2 (n = 12) whorls or no facial hair whorl (n = 18). Bulls with no facial hair whorls were not included in the analysis. Facial hair whorls were categorized by 2 distinct characteristics: having a round epicenter or having a non-round epicenter. Bulls with 1 or 2 facial hair whorls with a round epicenter had a higher percentage of morphologically normal spermatozoa (79 ± 1.5%) than bulls with 1 or 2 facial hair whorls with a non-round epicenter (71 ± 2.1%; P=0.005). Age of bull did not have a significant effect on percentage of normal spermatozoa (P = 0.80). Bulls with facial hair whorls with a round epicenter were more likely to have satisfactory spermatozoal morphology scores (70% morphologically normal spermatozoa ) than bulls with facial hair whorls with non-round epicenters (P 0.002). Eighty-two percent of bulls with facial hair whorls with round epicenters had satisfactory spermatozoal morphology scores, while only 57% of bulls with facial hair whorls with non-round epicenters had satisfactory morphology scores. It is possible that a facial hair whorl could be used as a visual aid in determining the quality, of spermatozoal morphology either during or prior to a BSE.

Fertilizing potential of semen containing a high percentage of sperm with a proximal droplet was evaluated using IVF. Design criteria: (a) specified semen with >100 x 106 sperm/mL with >40% progressively motile spermatozoa, after collection via electro-stimulation; (b) designated a droplet group, bulls whose semen contained >30% spermatozoa with a proximal droplet and <25% with other morphological abnormalities, and a control group, with <25% abnormalities of any type; and (c) stipulated evaluations at 11 to 13 mo of age and again ∼4 wk later. At the initial evaluation, when a bull was assigned to the droplet group, the next bull meeting control criteria was designated his pair; 15 pairs in four herds were studied. Semen was extended in egg-yolk citrate, cooled to 5°C over ∼2.5 h, and held at 5°C. After 20 to 44 h, spermatozoa were processed by swimup, incubated with heparin, and co-cultured with oocytes (35 to 56 oocytes/sample; 18 h). Ova were observed for cleavage ∼42 h after co-culture, and further development was evaluated on day 8. At first evaluation, cleavage rates were 18 and 46% for droplet and control groups (P<0.01); semen had 34 to 70% and 0 to 12% droplet spermatozoa. For 10 of 15 droplet bulls, <10% of ova were cleaved whereas cleavage rate was >15% for all control bulls. At second evaluation, only three droplet bulls still had >30% of spermatozoa with a proximal droplet. Cleavage rates increased accordingly; only four droplet bulls had <10% cleaved ova and 10 had ≥34% cleaved ova. Three control bulls had <10% cleaved ova and nine had ≥34% cleaved ova. Considering all 60 ejaculates, correlation between percentage of spermatozoa with a proximal droplet and percentage of cleaved ova was −0.49 (P<0.01). Correlations between percentages of motile or normal spermatozoa in field evaluations and outcome in IVF were 0.28 and 0.52. Laboratory evaluations of spermatozoa concomitant with preparation for IVF revealed that only incidence of proximal droplets appeared related to outcome in IVF. We concluded: (a) semen from most yearling beef bulls with a high incidence of proximal droplet spermatozoa had severely compromised IVF fertility; (b) as these bulls matured, the incidence of proximal droplets decreased, and IVF fertilizing potential increased; and (c) semen containing >30% spermatozoa with a proximal droplet is strong evidence that fertilizing potential of the bull will be low until the incidence decreases.

The National Animal Health Monitoring System (NAHMS) was established due to the need for information concerning the incidence of animal disease and the associated costs of disease. Three basic components were proposed in the pilot phase of NAHMS. They were the epidemiologic component, the economic component, and the evaluation component. The epidemiologic component was concerned with collection of data about disease incidence, including information related to identification of risk factors for disease. The economic component attached monetary significance to health occurrences. It also associated cost/benefit ratios with various management decisions and characteristics of individual operations. Food animal veterinary practitioners increasingly deal with animals on a population basis and can use this information in their animal health programming efforts. The third major component of the NAHMS pilot program in Colorado was the evaluation. Evaluation of the pilot project was essential to improve the program, to provide public accountability, to increase knowledge about it, and to provide assessment criteria for future development. There were two primary areas of focus in the evaluation process. They were the methodology of the study, which included the data collection methods and the procedures used to validate and analyze the data, and NAHMS itself, including input from participants.

Administration of exogenous glucocorticoids has been shown to enhance deposition of intramuscular fat in cattle. In this study, six pairs of genetically identical (cloned) steers were used to determine the effects of an implant containing 100 mg of dexamethasone on intramuscular fat deposition and on other carcass and meat quality traits. One steer in each pair served as a negative control (CON), whereas the other steer received a dexamethasone implant 30 to 60 d from slaughter (DEX). Treatment with dexamethasone did not (P > .05) enhance intramuscular fat deposition. However, DEX steers had greater (.33 cm; P < .05) thickness of external fat, larger (5.94 cm2; P < .05) longissimus muscle areas, and higher (1.9 percentage points; P < .05) dressing percentages than did CON steers. In addition, treatment with dexamethasone increased (P < .01) serum insulin concentrations. Dexamethasone had no effect (P > .05) on cooked beef palatability traits or on 24-h calpastatin activity. Although the DEX implant tested in this study was not effective for improving carcass quality grade, use of the implant increased external fat thickness and was effective for increasing carcass muscularity and dressing percentage.

The effect of morbidity during early life on the weaning weight of calves in Colorado beef herds was investigated as part of a prospective longitudinal observational study. A total of 2609 calves born in nine participating herds during the 1990 and 1991 calving seasons were monitored for disease events and subsequently weighed at weaning as a measure of performance. Morbidity outcomes of interest and their observed incidence rates were: general neonatal (to 45 days) morbidity, 2.6%; neonatal diarrhea, 1.0%; neonatal respiratory disease, 1.0%; and mothering problems/weak calves, 0.4%. Mean calf weaning weight was 244±46 kg. Weaning weight data were adjusted by multiple regression for the effects of the herd, year, age of the calf, age of the dam, calf sex, frame size of the dam, and twin birth. General morbidity during the neonatal period resulted in a 15.9 kg reduction (P<0.01) in calf weaning weight. When morbidity was investigated as more specific disease conditions, calves that were classified as mothering problems/weak calves (i.e. calves that experienced maternal neglect, abandonment, or starvation, and weak calves) weighed 24.4 kg less (P<0.01) at weaning than did non-afflicted calves. Respiratory conditions and diarrhea during the neonatal period resulted in 16.5 kg (P<0.01) and 10.7 kg (P<0.05) reductions in weaning weight, respectively. Thus, disease occurrence during the early life of the calf had a detrimental effect on weaning weight.

A prospective study was conducted to quantify the individual animal and maternal factors that affected morbidity and mortality of calves in Colorado beef herds. The study subjects were all calves born in ten participating herds during the 1990 and 1991 calving seasons. All 3666 calves born during the study period were individually identified at birth, and subsequent disease events were recorded by the producers. The disease outcomes of interest and their observed incidence rates were: perinatal (birth to 12 h) mortality, 2.5%; general neonatal (12 h to 45 days) mortality, 2.2%; general neonatal morbidity, 4.4%; neonatal diarrhea, 1.1%; neonatal respiratory disease, 1.0%; mothering problems/weak calves, 1.2%; and neonatal enterotoxemia/sudden death, 1.4%. Data analysis utilized multiple logistic regression. All analyses were adjusted for herd. Perinatal mortalily was greater (P<0.01) for calves experiencing dystocia and for twin calves. The incidence of general neonatal morbidity was also higher (P<0.01) among calves born to difficult or twin births, and calves of 2-year-old dams (P=0.06). General neonatal mortality was higher (P<0.05) among twins and calves of 2-year-old dams. Difficult or twin birth, as well as 2-year-old dam were the most common risk factors associated with the more specific morbidity outcomes. No evidence of the dam's late-gestation level of nutrition or seasonal effects on morbidity and mortality were observed.

Vesicular adenitis syndrome was diagnosed in 69.3% (52/75) of a group of yearling bulls on breeding soundness examination. Association of Haemophilus somnus infection with vesicular adenitis syndrome was confirmed in these bulls by microbial culture of vesicular gland fluid or semen samples and serologic testing.

The veterinarian is in a unique position to assist and improve the profitability of producers by educating clients on proper intervention and delivery techniques. This paper describes some procedures for intervention, evaluation, and management of dystocia by mutation, forced extraction, and fetotomy. In addition, a brief summary of the factors influencing dystocia is presented. When these techniques are used properly, losses due to dystocia are minimized.

This study was conducted to evaluate the effectiveness of a Trichomonas fetus vaccine to protect heifers from infection when bred to infected bulls. The vaccine consisted of a whole cell vaccine of T. fetus organisms stabilized in formaldehyde and adjuvanted in a mineral oil base. In the trial, fewer vaccinated heifers became infected than unvaccinated controls (69.4 vs 93.0%, respectively; P<0.08). The vaccinated heifers tended to clear the infections sooner than the controls (48.9 vs 68.5 days, respectively; P<0.10). The average number of days open was shorter in the vaccinated heifers than in the controls (33.2 vs 56.9 days, respectively; P<0.07). The first service conception rate was higher in the vaccinated heifers than in the controls (66.7 vs 33.3%, respectively; P<0.05). The number of services per conception in conceiving heifers was lower in vaccinated than in control heifers (1.44 vs 1.73, respectively; P<0.16). Cervicovaginal mucus (CVM) samples were collected every 14 days following first challenge (first service). On average, more CVM samples were positive for T. fetus for a longer period of time in the control than in the vaccinated heifers (3.9 vs 1.85 sampling periods, respectively; P<0.08). We concluded that, under the conditions of this trial, some protection to T. fetus was afforded by double vaccination with a whole cell vaccine. However, vaccination does not completely prevent heifers from developing infection.

Seventy-three Colorado cow/calf operations were monitored for calf mortality from birth to weaning as part of their participation in the National Animal Health Monitoring System. Producer-observed causes of calf mortality, and the costs associated with these deaths were obtained. The overall calf mortality during the study was 4.5%, with a total associated cost of $237,478. The mean cost per calf death was $216, of which $208 was attributed to the potential value of the calf and an additional $8 was for veterinary, drug, producer's labor, and carcass disposal expenses. The most commonly reported causes of calf mortality were dystocia (17.5%), stillbirth (12.4%), hypothermia (12.2%), diarrhea (11.5%), and respiratory infections (7.6%). These 5 disease conditions accounted for > 60% of all calf deaths. A cause was not determined for 19.7% of the calf deaths. Beef producers and veterinarians have the potential to decrease calf mortality and increase profits in cow/calf operations by implementing management strategies and herd health programs designed to decrease the number of calf deaths caused by these disease conditions.

Eighteen culled dairy cows were randomly allocated into 1 of 5 treatment groups. Six cows were vaccinated twice (2V), 21 days apart, 3 with whole cell (2WC) and 3 with fragmented cell membrane (2FC) containing 1 x 10(9)Trichomonas fetus organisms or protein equivalent in a commercial mineral oil adjuvant vaccine. Six more cows were vaccinated once (1V), 3 with whole cell (1WC) and 3 with fragmented cell vaccine (1FC), using the same vaccine, while 6 cows were used as the unvaccinated controls. All cows were challenged with 1 x 10(5) organisms 4 weeks after the second or the only vaccination. After challenge, cervico-vaginal mucus (CVM) samples were cultured for T . fetus weekly for 9 weeks. Whole cell vaccines were superior to fragmented cell vaccines, and both performed better than no vaccination for apparent elimination of trichomonad infections in dairy cows. In addition, 2V was superior to 1V, which, in turn, was superior to no vaccination. Furthermore, clearance time was reduced most by 2V and whole cell vaccination compared with 1V and fragmented cell vaccination. Clearance time was decreased significantly in all vaccinated cows compared with that in unvaccinated cows.

The relationship between serving capacity and pasture mating performance of 18 yearling beef bulls was evaluated. Six hundred yearling heifers were allotted into six groups. Treatment 1 consisted of two breeding pastures (replicates), each containing 100 nonsynchronized heifers and three high serving capacity bulls. Treatment 2 was identical except that the heifers were synchronized with prostaglandin F2α (25 mg, i.m.). Treatment 3 was similar to Treatment 1 except that the three bulls in each pasture were of low serving capacity. Following a 44-day breeding season, nonsynchronized heifers exposed to low serving capacity bulls had higher (P < 0.001) pregnancy rates (84%) than nonsynchronized heifers exposed to high serving capacity bulls (71%). More (P < 0.05) synchronized heifers exposed to high serving capacity bulls became pregnant during the first half of the breeding season (59%) compared with nonsynchronized heifers exposed to high serving capacity bulls (50%); however, the overall pregnancy rates did not differ (77 vs 71%). Replicates within Treatment 2 varied greatly; in the first 22 days of the breeding season, replicate pregnancy rates were 41 vs 77% which indicates that estrus synchronization and natural mating at standard bull to female ratios is feasible for some yearling bulls. There were no significant differences among treatments in average expected calving date or actual calving date. Improved serving capacity test results for low serving capacity bulls following the breeding season point out the slow learner or experience factor dilemma involved with serving capacity testing of yearling bulls. Sexual experience provided during the breeding season improved serving capacity scores for low serving capacity bulls. However, both the prebreeding and postbreeding serving capacity test results were poor predictors of bulls' actual pasture mating fertility.

Eighty-six cow-calf operations involved in the Colorado National Animal Health Monitoring System were monitored for a 12-month period, and data were collected on the incidence, prevention, and costs of disease. The costs of veterinary services and vaccines/drugs used in the treatment and prevention of disease conditions in these beef herds were determined and expressed on a per cow basis. Beef producers in this study spent an average of $2.04 ($0 to $29.88) per cow annually on veterinary services for treatment of disease conditions. The cost of veterinary services was a relatively small percentage (5.4%) of the total mean cost of disease incidence. The reproductive tract disease class was the most costly class in terms of veterinary services for disease treatment ($0.99/cow). Dystocia was the disease condition with the largest veterinary treatment cost. The total mean annual cost of drugs used in the treatment of disease conditions was $1.22/cow. The enteric, miscellaneous, and respiratory tract disease classes had similar mean drug costs for disease treatment and ranged from $0.31 to $0.39/cow. The total mean annual cost of veterinary services for administration of preventive measures in these herds was $1.85/cow ($0 to $12.03). Pregnancy examination, breeding soundness examination in bulls, brucellosis vaccination, pulmonary arterial pressure test, and campylobacteriosis vaccination accounted for over 90% of the money spent for preventive veterinary services. Approximately 60% of the total mean annual disease prevention cost was attributed to the purchase of vaccines/drugs ($6.59/cow).(ABSTRACT TRUNCATED AT 250 WORDS)